Airtec Motorsport Cosworth Inlet Plenum Upgrade – Fits 2WD & 4WD
A tried, tested and proven plenum upgrade for 2WD and 4WD Cosworth YB engines, with benefits that scale up with the level of tune.
The original plenum doesn't distribute airflow evenly across all four cylinders — its design favours the two centre cylinders closest to the entry point, creating both a flow restriction and uneven cylinder temperatures that can lead to "hotter" cylinders prone to issues. Airtec's redesigned plenum uses internal diffusers to divide and direct air more evenly across all four cylinders, reducing restriction and improving throttle response and power, with the biggest gains seen after remapping to suit the new flow characteristics — up to 45bhp in back-to-back testing, along with lower and more even exhaust gas temperatures across the cylinders.
The cast aluminium plenum is finished in natural silver and drilled for the original 2WD or 4WD throttle body, supplied with O-rings for the manifold flange and throttle body. An optional throttle cable bracket, throttle body butterfly lever, and a custom fluoro-lined power steering hose (needed only on earlier engines with the pump mounted below the throttle body) are also available.
Key Features
- Proven and tested to work — evenly distributes flow across cylinders
- Internal diffusers divert and direct air equally
- Gains in power and torque, more effective at higher power levels
- Evens out cylinder temperature differences — no "hot" cylinders
- Strong alloy casting resistant to splitting under high boost pressure
- O-ring gaskets for throttle body and main manifold flanges included
Compatible With
- Ford Sierra/Escort Cosworth (YB engine), 2WD and 4WD
